HPE 225 C4 P1
1. Q: What are the three main categories of dietary carbohydrates?
A: Simple carbohydrates, complex carbohydrates, and dietary fiber.
2. Q: What are simple carbohydrates also known as?
A: Sugars.
3. Q: What two subcategories make up simple carbohydrates?
A: Monosaccharides and disaccharides.
4. Q: Define “monosaccharides.”
A: Single sugar molecules that cannot be broken down further; examples include glucose, fructose, and galactose.
5. Q: Define “disaccharides.”
A: Double sugars formed by the combination of two monosaccharides, such as maltose, sucrose, and lactose.
6. Q: What is glucose commonly called?
A: Dextrose or grape sugar.
7. Q: What is fructose commonly called?
A: Fruit sugar or levulose.
8. Q: What is galactose found in?
A: It’s part of lactose, the sugar in milk.
9. Q: When two monosaccharides combine, what process occurs?
A: Dehydration synthesis forming a disaccharide.
10. Q: Name the three major disaccharides and their monosaccharide components.
A:
Sucrose: Glucose + Fructose
Lactose: Glucose + Galactose
Maltose: Glucose + Glucose
11. Q: What are “refined sugars”?
A: Purified forms of sugars isolated from foods, such as table sugar and corn syrup.
12. Q: What is “high-fructose corn syrup”?
A: A manufactured carbohydrate made by converting glucose in corn starch to fructose.
13. Q: What are complex carbohydrates commonly known as?
A: Starches or polysaccharides.
14. Q: Define “polysaccharide.”
A: A carbohydrate molecule made up of many glucose units, often thousands, linked together.
15. Q: What are the main types of plant starches?
A: Amylose, amylopectin, and resistant starch.
16. Q: What is glycogen?
A: The storage form of carbohydrate in animals and humans, stored in the liver and muscles.
17. Q: What are glucose polymers?
A: Polysaccharides prepared commercially by controlled hydrolysis of starch, often used in sports drinks (e.g., maltodextrins).
18. Q: What is the general energy yield per gram of carbohydrate?
A: 4 kilocalories (kcal) per gram.
19. Q: What are the three fiber categories defined by the National Academy of Sciences?
A: Dietary fiber, functional fiber, and total fiber.
20. Q: Define “dietary fiber.”
A: Nondigestible carbohydrates and lignin that are intrinsic and intact in plants.
21. Q: Define “functional fiber.”
A: Isolated or synthetic nondigestible carbohydrates that have beneficial physiological effects in humans.
22. Q: Define “total fiber.”
A: The sum of dietary fiber and functional fiber.
23. Q: Give examples of dietary fiber.
A: Cellulose, hemicellulose, lignin, pectin, gums.
24. Q: Give examples of functional fiber.
A: Isolated pectins, gums, and resistant starch.
25. Q: What is the difference between soluble and insoluble fiber?
A: Soluble fibers dissolve or swell in water; insoluble fibers do not.
26. Q: Examples of water-soluble fibers?
A: Gums, beta-glucans, and pectins.
27. Q: Examples of water-insoluble fibers?
A: Cellulose, hemicellulose, and lignin.
28. Q: What health benefits are associated with soluble fiber?
A: Helps lower blood cholesterol and control blood glucose.
29. Q: What are “added sugars”?
A: Refined sugars added to foods during processing or preparation.
30. Q: What are examples of added sugars?
A: Table sugar, honey, molasses, maple syrup, fruit juice concentrates.
31. Q: According to the Dietary Guidelines for Americans, what percentage of total kcal should come from added sugars?
A: No more than 10%.
32. Q: What is the RDA for carbohydrates for adults and children?
A: 130 grams per day.
33. Q: What percentage of total daily calories should come from carbohydrates (AMDR)?
A: 45–65% of total daily energy intake.
34. Q: What is the Daily Value (DV) for carbohydrates based on a 2,000 kcal diet?
A: 300 grams per day.
35. Q: What is the Acceptable Macronutrient Distribution Range (AMDR)?
A: The range of intake for a nutrient that is associated with reduced disease risk and adequate nutrient intake.
36. Q: What is the Adequate Intake (AI) for total fiber?
A:
Men ≤50 yrs: 38 g/day
Women ≤50 yrs: 25 g/day
Men >50 yrs: 30 g/day
Women >50 yrs: 21 g/day
37. Q: What is the current average fiber intake in the U.S.?
A: About 15 grams per day.
38. Q: What foods are high in carbohydrate content?
A: Grains, fruits, vegetables, dairy, beans, sports drinks, bars, gels, and candies.
39. Q: What are sports drinks typically composed of?
A: 6–8% carbohydrate solutions containing glucose, fructose, sucrose, or glucose polymers.
40. Q: How much carbohydrate does a typical 8-oz sports drink contain?
A: Approximately 14–18 grams.
41. Q: What is the primary function of carbohydrates in nutrition?
A: To provide energy.
42. Q: What percentage of the brain’s metabolism is from glucose?
A: About 50% of total body glucose utilization.
43. Q: What is the process that breaks down carbohydrates during digestion?
A: Enzymatic hydrolysis.
44. Q: What enzyme begins carbohydrate digestion in the mouth?
A: Salivary amylase.
45. Q: What enzyme continues carbohydrate digestion in the small intestine?
A: Pancreatic amylase.
46. Q: What are the final end products of carbohydrate digestion?
A: Monosaccharides (glucose, fructose, galactose).
47. Q: Where does most carbohydrate absorption occur?
A: The small intestine, through villi.
48. Q: Define “active transport.”
A: The movement of molecules across a cell membrane using energy.
49. Q: Define “facilitated diffusion.”
A: The transport of substances across a cell membrane by means of a carrier protein without energy.
50. Q: What is “osmosis”?
A: The passive diffusion of water through a semipermeable membrane.
51. Q: What is “dumping syndrome”?
A: Gastrointestinal distress from high sugar concentrations drawing water into the intestines, causing diarrhea and weakness.
52. Q: What is lactose intolerance?
A: The inability to digest lactose due to low lactase enzyme levels.
53. Q: What happens to fructose and galactose after absorption?
A: They are converted to glucose by the liver.
54. Q: What is the normal range for blood glucose levels?
A: 80–100 mg/dL.
55. Q: Define “hyperglycemia.”
A: High blood glucose levels (>140 mg/dL).
56. Q: Define “hypoglycemia.”
A: Low blood glucose levels (<50 mg/dL).
57. Q: What is the “glycemic index (GI)”?
A: A ranking system that measures how quickly carbohydrate foods raise blood glucose levels compared to glucose (GI=100).
58. Q: What are the GI categories?
A:
High: ≥70
Medium: 56–69
Low: ≤55
59. Q: Define “glycemic load (GL).”
A: A measure that considers both the glycemic index and the amount of carbohydrate in a serving of food.
60. Q: Formula for glycemic load?
A: GL = (GI × grams of nonfiber carbohydrate per serving) ÷ 100.
61. Q: GL ranking scale values?
A:
High: ≥20
Medium: 11–19
Low: ≤10
62. Q: What factors affect a food’s glycemic index?
A: Processing, physical form, fiber content, fat, and protein.
63. Q: Give an example of a low-GI food.
A: Lentils or kidney beans.
64. Q: Give an example of a high-GI food.
A: Baked potato or white bread.
65. Q: What hormone regulates blood glucose by promoting uptake into cells?
A: Insulin.
66. Q: What hormone increases blood glucose when it drops too low?
A: Glucagon.
67. Q: What are GLUT-4 receptors?
A: Glucose transporters in muscle and fat cells activated by insulin and exercise.
68. Q: What is “reactive hypoglycemia”?
A: A rapid drop in blood glucose following a high-insulin response after eating simple sugars.
69. Q: Which foods lead to slower insulin responses and stable blood glucose levels?
A: Low-GI foods, especially those high in soluble fiber.
70. Q: What are the four major fates of blood glucose?
A: Energy use, storage as glycogen, conversion to fat, or excretion in urine.
71. Q: Where is glycogen stored in the body?
A: In the liver and skeletal muscles.
72. Q: How much glycogen does the liver store?
A: About 75–100 grams (300–400 kcal).
73. Q: How much glycogen do muscles store?
A: About 300–400 grams (1,200–1,600 kcal).
74. Q: Total carbohydrate energy stores in the body?
A: About 1,800–1,900 kcal total.
75. Q: What is a “millimole (mmol)”?
A: 1/1,000 of a mole, used to measure concentration of substances like glucose.
76. Q: What is gluconeogenesis?
A: The formation of new glucose in the liver from non-carbohydrate sources like protein and fat.
77. Q: What is the glucose-alanine cycle?
A: The conversion of amino acid alanine into glucose in the liver.
78. Q: What is the Cori cycle?
A: The process where lactate from muscles is converted into glucose in the liver.
79. Q: Can fat be converted into glucose?
A: Only the glycerol component of fat can be; fatty acids cannot.
80. Q: What is the main function of carbohydrates in the body?
A: To supply energy for all body functions, especially the brain and muscles.
81. Q: What is the primary energy source for the brain and CNS?
A: Glucose.
82. Q: What percentage of muscle energy needs during rest comes from carbohydrates?
A: About 15–20%.
83. Q: How many ATP molecules are produced from aerobic metabolism of glucose?
A: About 29–32 ATP per glucose molecule.
84. Q: How many ATP molecules are produced from anaerobic glycolysis starting with glycogen?
A: 3 ATP.
85. Q: Define “glycolysis.”
A: The breakdown of glucose for energy.
86. Q: What are glycoproteins?
A: Carbohydrate-protein complexes in cell membranes that serve as receptors.
87. Q: What is ribose?
A: A five-carbon sugar used in RNA and ATP structure.
88. Q: Why is carbohydrate called the “master fuel” for athletes?
A: It provides the quickest and most efficient energy for high-intensity exercise.
89. Q: During rest, what proportion of total energy comes from carbohydrates?
A: About 40%.
90. Q: What energy systems use carbohydrate?
A: Both anaerobic (lactic acid system) and aerobic (oxygen system).
91. Q: What is the “crossover concept”?
A: The point at which carbohydrate becomes the predominant fuel source as exercise intensity increases.
92. Q: When does carbohydrate become the exclusive fuel?
A: During maximal or supramaximal exercise.
93. Q: What causes fatigue during intense, short exercise (<1 min)?
A: Accumulation of hydrogen ions from lactic acid.
94. Q: What causes fatigue during prolonged exercise?
A: Depletion of liver and muscle glycogen.
95. Q: How does heat affect carbohydrate metabolism?
A: It increases glycogen utilization due to elevated epinephrine and hyperthermia.
96. Q: What is the effect of altitude on carbohydrate metabolism?
A: Increased carbohydrate oxidation and glycogen use.
97. Q: Why is carbohydrate a more efficient fuel than fat?
A: It produces more ATP per liter of oxygen consumed.
98. Q: How much more efficient is carbohydrate metabolism than fat oxidation?
A: About 7–17% more efficient in ATP production.
99. Q: What is the main carbohydrate source of energy during exercise?
A: Muscle glycogen.
100. Q: What happens to liver glycogen during prolonged exercise?
A: It breaks down to maintain blood glucose and prevent hypoglycemia.